There are many places to stay in the Chianti region that are less expensive.
San Gimignagno, not far from Monteriggoni has some lovely hotels, we stayed
there 5 years ago for 5 nights and used it as a base and were able to see a
fair bit of the country side. As well from what I have heard and read,
around Siena, also not far from Monteriggoni, there are many places - Karen
Brown's book - Inns and Itineraries in Italy has some lovely places.

Last year we stayed just outside of Cortona at Locanda del Molina (from
Karen Brown) it was just over $100 Canadian dollars and had a wonderful
breakfast and an even better dining room for dinners that were wonderful and
a good value.